For the Position-Time graph, the y-axis represents position as the x-axis represents time, thus representing velocity as a whole. In this case, position is the measurement of distance, in meters, away from the motion detector. When something moves away from the motion detect, the y-coordinate increase, and vice versa. As for the x-axis, time is measured in seconds, increasing from zero to infinity as the x-axis moves to the right.
When combined into a slope (y/x) ration, there may be a positive, zero, and/or negative slope. At a positive slope, the object is moving away from the motion detector, at a zero slope, the object is not moving any distance at all, and at a negative slope, the object is moving towards the motion detector. Since velocity is displacement over time, the slope increases in steepness as the object moves faster in the relative direction, and vice versa. Eventually, if there is a negative slope, the line may continue to move towards the x-axis, but never cross it because a negative y-coordinate will mean that the object has moved past motion detector as it moves toward the detector. Although this is physically possible, it is graphically impossible because doing so will remove the object from the detector's line of sight.
For the Velocity-Time graph, the y-axis represents velocity as the x-axis represents time. In the experiment, velocity is meters per second and time is seconds, so the graph as a whole represents acceleration, which is meters per second per second. Hence, the motion detector will record how and when an object changes velocity.
Like the Position-Time graphs, the Velocity-Time graph may also have positive, zero, and/or negative slopes, but unlike the P-T graphs, V-T graphs may pass the x-axis. The V-T graphs are allowed to pass the x-axis because velocity can be positive, moving away from the detector, or negative, moving towards the detector. Therefore, if the object is moving towards the detector, velocity will be negative, thus resulting in a negative y-coordinate which will lie below the x-axis.
A positive slope above the x-axis indicates that the object is positively accelerating as it moves away from the detector. On the other hand, if the positive slope is below, the x-axis, then it means that the object is negatively "decelerating" as it moves towards the detector. A zero slope anywhere indicates that the object has stopped accelerating, though it can still be moving. When the negative slope is above the x-axis, it means the object is slowing down as it moves away from the detector, and when the negative slope is below the x-axis, it means the object is speed up as it return towards the detector. Like the P-T graphs, a steeper slope indicates how fast the rate of change is, which in this case shows how fast the object is accelerating. The opposite is also true.
When combined into a slope (y/x) ration, there may be a positive, zero, and/or negative slope. At a positive slope, the object is moving away from the motion detector, at a zero slope, the object is not moving any distance at all, and at a negative slope, the object is moving towards the motion detector. Since velocity is displacement over time, the slope increases in steepness as the object moves faster in the relative direction, and vice versa. Eventually, if there is a negative slope, the line may continue to move towards the x-axis, but never cross it because a negative y-coordinate will mean that the object has moved past motion detector as it moves toward the detector. Although this is physically possible, it is graphically impossible because doing so will remove the object from the detector's line of sight.
Like the Position-Time graphs, the Velocity-Time graph may also have positive, zero, and/or negative slopes, but unlike the P-T graphs, V-T graphs may pass the x-axis. The V-T graphs are allowed to pass the x-axis because velocity can be positive, moving away from the detector, or negative, moving towards the detector. Therefore, if the object is moving towards the detector, velocity will be negative, thus resulting in a negative y-coordinate which will lie below the x-axis.
A positive slope above the x-axis indicates that the object is positively accelerating as it moves away from the detector. On the other hand, if the positive slope is below, the x-axis, then it means that the object is negatively "decelerating" as it moves towards the detector. A zero slope anywhere indicates that the object has stopped accelerating, though it can still be moving. When the negative slope is above the x-axis, it means the object is slowing down as it moves away from the detector, and when the negative slope is below the x-axis, it means the object is speed up as it return towards the detector. Like the P-T graphs, a steeper slope indicates how fast the rate of change is, which in this case shows how fast the object is accelerating. The opposite is also true.